A relay lens driving device provided in an optical head moves a relay lens in the direction of an optical axis thereof to correct a spherical aberration that may be caused by an error in the thickness of a cover layer of an optical disk. The relay lens driving mechanism has a lens to correct spherical aberrations, a lens holder which holds the lens, a first parallel plate spring which supports the lens holder at one end thereof, an intermediate member attached to the other end of the first parallel plate spring, a second parallel plate spring arranged to extend from the intermediate member to the lens holder to support the intermediate member at one end thereof, and a fixing member which fixes the other end of the second parallel plate spring.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An optical head comprising: a lens to correct spherical aberrations; a lens holder holding the lens; a guide rail extending parallel with an optical axis of the lens; a rail receiving section provided in the lens holder to receive the guide rail; a coil secured to the lens holder and having a winding axis extending perpendicularly to the guide rail; a permanent magnet provided opposite the coil; and a pressing section pressing the rail receiving section against the guide rail.
2. An optical head according to claim 1 , further comprising a second guide rail extending parallel with the optical axis of the lens and a second rail receiving section provided in the lens holder to receive the second guide rail.
3. An optical head according to claim 2 , wherein the pressing section is a magnetic material piece provided in the lens holder to cooperate with the permanent magnet in generating pressing force which presses the guide rail against the rail receiving section.
4. An optical head according to claim 2 , wherein a winding axis for the coil lies at predetermined angle from a plane containing centers of the first and second guide rails, and a line, which extends from the magnetic material piece in a direction perpendicular to the plane containing the centers of the guide rails, crosses the plane at a point between the first and second guide rails.
5. An optical head according to claim 2 , further comprising a base holding the first and second guide rails and the permanent magnet, and a second lens fixed to the base and having an optical axis coinciding with that of said lens.
6. An optical head according to claim 1 , wherein the pressing section is a magnetic material piece provided in the lens holder to cooperate with the permanent magnet in generating pressing force pressing the guide rail against the rail receiving section.
7. An optical head according to claim 1 , wherein the permanent magnet is magnetized so as to have two poles provided in an axial direction of the guide rail.
8. An optical head according to claim 1 , wherein the guide rail is arranged along a circumferential direction of the optical axis.
9. An optical disk apparatus including an optical head that irradiates an optical disk with a light beam, the optical disk apparatus comprising: a lens to correct spherical aberrations; a lens holder holding the lens; a guide rail extending parallel with an optical axis of the lens; a rail receiving section provided in the lens holder to receive the guide rail; a coil secured to the lens holder and having a winding axis extending perpendicularly to the guide rail; a permanent magnet provided opposite the coil; a pressing section pressing the rail receiving section against the guide rail; and a lens moving section moving the lens in a direction of an optical axis.
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October 17, 2005
May 29, 2007
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